1. Field of the Invention
The invention relates to a playback method and apparatus for reading audio programs that were recorded on a record carrier.
2. Description of the Related Art
In a co-pending U.S. patent application, entitled "Record Carrier, and Recording Method and Apparatus for Recording Audio Programs on a Track of a Record Carrier," and filed by the Applicant, there is disclosed a record carrier, such as a compact disc, which includes a number of tracks having a number of blocks. As shown in FIG. 1, each block (B) includes a plurality of interleaved compressed audio programs, and is grouped into a number of consecutive sub-blocks. Each of the compressed audio programs is segmented to form a number of consecutive audio sectors (AS(i,j), i=0 to 5, j=0 to k-1) that is equal in number to the sub-blocks. The audio sectors AS(i,j) of the compressed audio programs are arranged among the sub-blocks such that a jth one of the audio sectors AS(i,j) of each of the compressed audio programs is disposed in a jth one of the sub-blocks.
The compressed audio programs are assigned with an ascending order of program numbers, and the audio sectors AS(i,j) in each of the sub-blocks are arranged in the ascending order of the compressed audio programs to which the audio sectors AS(i,j) belong. As shown in FIG. 2, each of the audio sectors AS(i,j) includes a SYNC field 10 for storing a SYNC word, an ID field 11 for storing an ID code that is unique for each of the audio sectors AS(i,j), a data field 12, and an error management code field 13 for storing an error management code.
Referring to FIG. 3, the ID field 11 includes a track number (TN), a block number (BN), a program number (PN), a sector number (SN), and connection information (CI). The track number (TN) indicates the track (T) of the record carrier to which the audio sector AS(i,j) belongs. The block number (BN) indicates the block (B) on the track to which the audio sector AS(i,j) belongs. The program number (PN) indicates the compressed audio program on the block (B) to which the audio sector AS(i,j) belongs, e.g. i=0 to 5 as shown in FIG. 1. The sector number (SN) indicates the sector number of the audio sector AS(i,j) in the compressed audio program to which the audio sector AS(i,j) belongs, e.g. j=0 to k-1 as shown in FIG. 1. The connection information (CI) contains flags for facilitating continuous playback of the compressed audio programs when the record carrier is read. The flags can include an end of program (EOP) flag, an end of block (EOB) flag, an end of track (EOT) flag, and an end of disc (EOD) flag. Particularly, the last audio sector of each of the compressed audio programs, i.e. AS(i,k-1), has an EOP flag. The last audio sector of each block (B), i.e. AS(5,k-1), further has an EOB flag. The last audio sector AS(5,k-1) of the last block (B) in a track further has an EOT flag. The last audio sector AS(5,k-1) of the last block (B) in the last track of the record carrier further has an EOD flag.
By virtue of the interleaving arrangement of the audio sectors on the record carrier, a high density of compressed audio programs can be recorded on tracks of the record carrier while retaining the constant linear velocity, i.e. 1.5 Mbits/sec, of a compact disc drive with a compressed audio bit rate of about 224 Kbits/sec, thereby obviating the need for the compact disc drive to alternate frequently between stalling and advancing states to minimize degradation of the compact disc drive when the compressed audio programs are read from the record carrier.